Inositol is a highly valued B-vitamin. Plants contain phytic acid {myoinositol 1,2,3,4,5,6-hexakis (dihydrogen phosphoric acid)} as the storage form of phosphorus. Phytic acid is found within plant cell structures as mineral bound complexes termed phytin. Phytin is largely insoluble at neutral pH. Phytic acid can also exist in solution in the salt form termed phytate. The terms “phytin” and phytate are often used interchangeably. In this disclosure, the term “phytate” is intended to refer to phytic acid, phytate and phytin, except where a distinction between these materials is made specifically.
Some of the partial hydrolysis products of phytate are inositol pentaphosphate (IP5), inositol tetraphosphate (IP4), inositol triphosphate (IP3), inositol diphosphate (IP2) and inositol monophosphate (IP1). These partial hydrolysis products of phytate can be hydrolyzed further to yield inositol. The obtaining of inositol from a plant material requires conversion of the phytate to inositol and purification of the inositol from other components in the plant starting material.
Producing inositol from plant material is difficult. One approach is to hydrolyze the phytate in an aqueous slurry, to yield various sugars including inositol. However, inositol is a neutral soluble sugar that is very similar in molecular size and charge characteristics to other sugars such as glucose that are often present in high levels in plant materials. Because of this, it can be difficult to separate the inositol from the other carbohydrates in the slurry.
Another approach to production of inositol from plant materials is to purify the phytate from the starting slurry and to hydrolyze the purified phytate to inositol in a later step in the overall process. However, because phytate in plants usually exists in the form of phytin, direct phytate purification from an aqueous slurry of plant materials requires solubilization of phytin and then separation of the phytate from the remainder of the components of the slurry. Efficient extraction, solubilization of phytin and separation from the remaining components of the slurry is difficult.